Prallethrin is a known insecticidal compound and described in The Pesticide Manual 10.sup.th edition, page 827 (British Crop Protection Council 1994). Its chemical name is (S)-2-methyl-4-oxo-3-prop2-ynylcyclopent-2-enyl (1R)-cis,trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate . Neonicotinoid compounds include amidine compounds and guanidine compounds having a nitro, cyano or trifluoroacetyl group, and described in, for example, U.S. Pat. No. 5,532,365, U.S. Pat. No. 4,742,060, U.S. Pat. No. 4,849,432, U.S. Pat. No. 5,034,404, U.S. Pat. No. 5,750,548, U.S. Pat. No. 5,304,566, EP-428941A and so on.